A5 is a stream cipher. A5 is based on a combination of three linear feedback shift registers (LFSRs) with irregular clocking. It uses 64 bit keys. The register lengths are 19, 22, and 23. All the feedback polynomials are sparse. The output is the XOR

A5 algorithm implemented

自己写的一段A5算法加密代码，使用的是C语言，可在DOS环境下输出64位密钥和22位随机帧。 -Write your own section A5 encryption algorithm code, using C language, can output 64-bit key and 22 random frames in the DOS environment.

A51 source code in C